Solar thermal technologies harness the thermal energy of the sun to provide heat for solar water heating, solar pool heating, and solar space heating. Click here to learn more
Solar Water Heating
Solar water heaters use the sun’s heat to provide hot water for a home or building. Most solar water heating systems have two main parts: a solar collector and a well-insulated storage tank. Some systems also have electric pumps.
Solar collectors absorb solar radiation (heat) and transfer the heat to potable water. There are two main types of collectors for residential and commercial applications: flatplate and evacuated-tube. Flatplate collectors, the most common type of solar collector, are insulated, weatherproof boxes that contain dark absorber plates under one or more transparent covers. Evacuated-tube collectors are made up of rows of parallel, transparent glass tubes in which the air is withdrawn from the space between the tubes to form a vacuum.
Solar water heating systems are either active or passive, though the most common systems are active. Active systems rely on pumps to move the water between the collector and the storage tank, while passive systems rely on gravity and water’s tendency to naturally circulate as it is heated.
Solar Swimming Pool Heaters
Solar swimming pool heaters can extend the swimming season by up to four months depending on locale and climate. Solar swimming pool heaters are relatively easy to integrate into existing pools because most pools already have a pump, filter, and plumbing. With a solar swimming pool heater, the pool’s filter pump sends the pool water through the filter and then through a solar collector instead of directly back to the pool. The sun heats the water in the collector and the water is then piped back to the pool. The collector is usually made of heavy-duty black plastic or rubber and can be mounted on the roof or anywhere else near the pool that provides the necessary exposure, orientation, and tilt toward the sun.
Solar Space Heating Systems
Solar space heating systems bring warm air into residential buildings in two different ways: passively and actively. Passive solar space heating captures some of the sun’s heat through design features as well as heat absorbent materials in walls or floors that absorb the suns heat during the daytime and then release it at night. Active solar space heating uses non-toxic liquid, water, or air as the heat-transfer medium in a solar energy collector. The heated liquid or air then circulates through the building or home by use of electric fans or pumps to transfer and distribute the heat.
Solar Cooling Systems
Solar cooling systems can be either an absorption chiller system or a desiccant system. Regular air conditioners use a compressor, while an absorption chiller uses solar heat to evaporate a fluid. This evaporation removes heat from the environment, creating a cooling effect. In a desiccant system, air passes over a common desiccant, such as silica gel, to draw moisture from the air and make the air more comfortable. Solar thermal energy dries the desiccant out to regenerate it.
Current solar air conditioning systems can be expensive investments. Solar cooling as a stand-alone application is rarely used because of the high initial costs; when used, it exists primarily in large-scale, commercial arenas. Solar cooling becomes less costly when combined with solar hot water heater and solar space heating systems.